When you're stressing against an opponent, remember, they're stressing just as much about you too

They might be. They might also be overconfident, or they might be rightly confident, or they might be rightly un-confident, etc. Knowing the difference is important, and is what's behind that Sun-tzu quote about knowing your enemy as well as yourself.

Hmm, she doesn't seem stressed, she just casually says "I am Malenia, Blade of Miquella..."

When you're stressing about an opponent, remember that you're hurting yourself and giving them an advantage. Don't do that.

Can't remember the last time I was in a fight with equal odds.

I'm pretty sure I have an anxiety disorder so I doubt it, but it's a nice sentiment haha